1. Field of the Invention
The present invention relates to a micro-electromechanical systems (MEMS) microphone and a method of manufacturing the same, and more particularly to a MEMS microphone which can be simply manufactured through an upper substrate process and a method of manufacturing the same.
2. Discussion of Related Art
A microphone is an apparatus which converts a voice into an electrical signal. Types of microphones include a dynamic type, a condenser type, a ribbon type, and a ceramic type. As electrical or electronic technology develops rapidly, microphone technology is also greatly improved, and as development of small-sized wireless or wire line devices is accelerated, the size of microphones is also gradually decreasing. In this regard, a micro-electromechanical systems (MEMS) microphone using MEMS technology has been recently developed.
MEMS microphones can be generally divided into a piezo type and a condenser type. The condenser-type MEMS microphone is more frequently used due to an excellent frequency response characteristic of a voice band.
FIG. 1 illustrates a conventional condenser-type MEMS microphone.
Referring to FIG. 1, a condenser-type MEMS microphone 100 is manufactured by an upper substrate process of forming a lower electrode 130 and a diaphragm 170 in an upper portion of a substrate 110 and a lower substrate process of forming a rear acoustic chamber 190 in a lower portion of the substrate 110.
First, in the upper substrate process, the lower electrode 130 is formed on the substrate 110, and a sacrificial layer-removing lower electrode hole 130a is formed in the lower electrode 130. A sacrificial layer 150 is formed on the lower electrode 130 at a predetermined thickness, and the diaphragm 170 is formed on the sacrificial layer 150. The diaphragm 170 includes an insulating layer 171 and an upper electrode 173, and is fixed to the substrate 110 by a diaphragm support 170a. 
Next, in the lower substrate process, after the diaphragm 170 is formed on the substrate 110, the upper portion of the substrate 110 is protected by an insular, and a lower portion of the substrate 110 is etched through bulk-type micromachining to form a rear acoustic chamber 190. Then, the sacrificial layer 150 is removed through the lower electrode hole 130a to form a vibration cavity 150a. 
As described above, according to the conventional art, since the lower substrate process is required in order to form the rear acoustic chamber 190, the manufacturing process is complicated. Therefore, there is a problem in that there is a limitation to increasing manufacturing throughput.